If you had the chance to decree that everyone—everyone—would have to watch one YouTube video all the way through and pay attention the entire time, what would it be? It could be something important, historic, funny, dumb, or just something that no one else seems to like nearly as much as you do and you desperately want to force everyone else to see it in the hope that somebody, anybody, gets it the way you do.
This isn't the only YouTube video people get to watch, it's just that yours is required watching. You can only pick one, and saying "I can't decide; here's three" is cheating, and cheating is not allowed! Choose wisely. Ready? Go.